There is known a vast variety of different devices used for transporting parceled goods. Typically pieces or stacks thereof are loaded onto a wheeled platform, on which they are conveyed to shop floor or storage. These wheeled platforms are called dollies. Some dollies are equipped with a tow bar for transporting a plurality of dollies in a chained fashion. When the tow bar for pulling the dolly is temporarily not used, it is typically pivoted in an upright position for saving space. U.S. Pat. No. 4,856,810 proposes one solution to providing a space saving tow bar for a dolly. The tow bar known from U.S. Pat. No. 4,856,810 must be manually manipulated into the vertical space saving position.
A solution for biasing the tow bar to the vertical position is proposed by EP 2278015, which discloses a biasing mechanism, which connects the tow bar to the dolly. The biasing mechanism includes an axle fixed to the dolly and a spring arranged around the axle and tensioned between the tow bar and the chassis of the dolly. The spring biases the tow bar to rotate it about the fixed axle towards an upright position. The biasing mechanism known from EP 2278015 has the additional benefit of assisting coupling between the tow bar and the receiving socket of another dolly.
The tow bars known from U.S. Pat. No. 4,856,810 and EP 2278015 are both permanently fixed to the dolly. Detachable tow bars are also known for retrofitting a tow bar to a dolly. Such tow bars typically feature a quick coupling between a plug on the tow bar and a corresponding socket, which is to be fixed to the dolly for receiving the tow bar. While detachable tow bars improve modularity of dollies, they lack the benefit of saving space by biasing the tow bar to an upright position.
It is therefore an aim of the present invention to provide a tow bar assembly, which may be retrofitted to a dolly while maintaining convenient space saving properties of permanently fitted tow bars.